digilib in controller | we omit REST-API

controller.xql

 xquery version "3.1";
 
 import module namespace config="http://textgrid.de/ns/SADE/config" at "modules/config/config.xqm";
+import module namespace digilib="http://textgrid.info/namespaces/xquery/digilib" at "../textgrid-connect/digilibProxy.xqm";
 
 declare variable $exist:path external;
 declare variable $exist:resource external;
@@ -11,25 +12,40 @@ declare variable $exist:root external;
 let $project := tokenize( $exist:path, "/" )[. != ""][not(ends-with(., "html"))][1]
 let $listproject := config:list-projects()[1]
 return
+
+    (: forward requests without resources to index.html :)
 if ($exist:path eq '') then
     <dispatch xmlns="http://exist.sourceforge.net/NS/exist">
         <redirect url="{request:get-uri()}/"/>
     </dispatch>
+
+    (: forward requests without project to the first project listed :)
 else if (empty($project)) then
         <dispatch xmlns="http://exist.sourceforge.net/NS/exist">
         <redirect url="{config:list-projects()[1]}/index.html"/>
     </dispatch>
 
+    (: forward requests without resources to index.html :)
 else if (ends-with($exist:path, "/") or empty($exist:resource)) then
-    (: forward root path to index.xql :)
     <dispatch xmlns="http://exist.sourceforge.net/NS/exist">
         <redirect url="index.html"/>
     </dispatch>
+
+    (: forward REST requests to data collection of the project:)
 else if (tokenize($exist:path, '/') = "rest") then
     <dispatch xmlns="http://exist.sourceforge.net/NS/exist">
-        <forward url="/../sade-projects/{$project}/data/xml/{substring-after($exist:path, "/rest/")}" >
-        </forward>
+        <forward url="/../sade-projects/{$project}/data/xml/{substring-after($exist:path, "/rest/")}"/>
     </dispatch>
+
+    (: forward DIGILIB requests to the proxy function :)
+else if (tokenize($exist:path, '/') = "digilib") then
+    let $path := tokenize($exist:path, '/'),
+        $id := $path[last()],
+        $if-modified-since := request:get-header("if-modified-since")
+    return
+        digilib:proxy($project, $id, $if-modified-since)
+
+    (: the important stuff :)
 else if (ends-with($exist:resource, ".html")) then
     let $doc-path := $config:projects-dir || $project || config:get("template") || $exist:resource
     return
@@ -45,13 +61,15 @@ else if (ends-with($exist:resource, ".html")) then
 			<forward url="{$exist:controller}/modules/view.xql"/>
 		</error-handler>
     </dispatch>
-(: Resource paths starting with $shared are loaded from the shared-resources app :)
+
+    (: resource paths starting with $shared are loaded from the shared-resources app :)
 else if (contains($exist:path, "/$shared/")) then
     <dispatch xmlns="http://exist.sourceforge.net/NS/exist">
         <forward url="/shared-resources/{substring-after($exist:path, '/$shared/')}">
             <set-header name="Cache-Control" value="max-age=3600, must-revalidate"/>
         </forward>
     </dispatch>
+
 else
     (:  check if the resource comes from the template or the data
         we try to leave the template manipulation as minimal as